Solar heating and central air conditioning with heat recovery system

ABSTRACT

The present invention discloses a solar heating and cooling central air-conditioning with a heat recovery system. The system includes a solar heating subsystem for providing supplementary energy to a heat pump, a buffer water tank for storing and minimizing energy loss, a domestic water heater for recovering unused heat, and an air handler ventilation and exchanger subsystem. All parts of the system are connected by antifreeze circulation pipes. The present invention combines the solar technology with the heat pump technology, making it work in extreme cold climate. The system is high energy efficient, versatile, safe, reliable, intelligent and flexible in installation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 61/771,547, filed on Mar. 1, 2013, which is hereby incorporated byreference.

FIELD OF THE INVENTION

The present invention relates to heat pump for providing heating andcentral air conditioning, and specifically relates to solar heating andcentral air conditioning with heat recovery system.

BACKGROUND OF THE INVENTION

Heat pumps are commonly used as heating ventilation and air conditioning(HVAC) or heating and cooling systems. A heat pump works as a two-waysystem, in either heating or cooling mode. It uses the principles ofreversed Carnot cycles, and uses a working medium to transfer the energystored in the environment from outdoor to indoor. This process onlyconsumes a small amount of power in comparing to the power required toheat or cool a place with pure electricity. Therefore, heat pumptechnology can save a lot of “high-grade” energy, e.g. electricity, inproviding heating and cooling needs.

A heat pump commonly uses outside air as the source. In heating mode,the outdoor coil functions as an evaporator, in which the low pressuremedium flowing through carries the thermal energy from the outside air,and is compressed by a compressor, which causes the fluid to turn intohighly pressurized vapor. The augmented medium then transfers the energyfrom the compression and the thermal energy carried from outside to heatinside the building. This is done by a heat exchanger or condenser andpressure-lowing device (e.g. expansion valve), where the high pressuredhot vapor cools down and becomes low pressure liquid while releasingheat to the surrounding. It enters into the outdoor coil again and thesame process repeats.

In cooling mode, the thermal energy movement is reversed via a reversingvalve. The reversing valve switches the direction of medium flow, andthe functions of evaporator and condenser swap. The medium arrives atthe compressor as a cool, low-pressured gas, is pressurized through thecompressor. The resulting hot, high-pressure vapor flows into theoutdoor coil that functions as the condenser, through which the mediumleaves the condenser as liquid at much lower temperature. The liquidgoes into the evaporator through a very tiny hole, through which theliquid's pressure drops. At the low pressure, the liquid begins toevaporate into a gas while extracting heat from the air around it. Theresulting low pressure gas returns to the compressor and the cyclerepeats.

There are two major types of heat pumps that use air as outside source:air to air and air to water systems. In an air to air system, heat isdirectly released to or extracted from surrounding air inside thebuilding. In an air to water system, heat is released to or extractedfrom a heating coil inside a water tank, which can be used as floorheating, domestic hot water heating to provide shower and hot water tapsin the building. A typical heat pump water heater comprises acompressor, evaporator, condenser, heat exchanger, axial fan, insulatedwater tank, water pump, fluid tank, filter control, electronic expansionvalve and electronic automatic controller. After power is on, the axialfan starts running, the outdoor or ambient air exchanges heat with theevaporator and the resulted lower temperature air is discharged by thefan. Meanwhile, the medium inside the evaporator extracts heat from theair and is vaporized into gas. The compressor then compresses this lowpressure working medium gas into the high-temperature, high-pressuregas, then feeds the gas into the condenser. Inside the condenser, thewater that is circulated by a water pump is heated by the workingmedium, then stored inside the insulated water tank. Meanwhile, theworking fluid going through the condenser is cooled to a liquid, thenflows through an expansion valve to become low pressure liquid beforegoing into the evaporator, and the cycle repeats. This process repeatsand gradually heats the water in the insulated water tank until itreaches about 131° F., a suitable temperature for shower and householduse.

Commercial systems, however, still suffer from less than idealperformance, measured by coefficient of performance (COP). For example,when used for heating on a mild day (e.g. outside temperature of 10°C.), a typical air-source heat pump achieves COP of 3˜4. Generally, aheat pump is more efficient in hotter climate than cooler climate, sowhen there is a wide temperature differential between the hot and cold(indoor and outdoor) in a cold climate, the COP is lower. Further, asthe heat pump extracts heat from outdoor air, moisture in the air maycondense and possibly freeze on the outdoor coil. In extreme coldweather, for example, around −18° C., the COP of a heat pump willapproach 1, which is less advantage than a simple electric based heater,thus it is not a commercially viable option. In practice, a heat pump incold climates often uses an electric heater or fossil fuel heatingsource as a backup system.

Therefore, there is a need to improve the efficiency of heat pumpsystems. There is further a need to keep a heat pump system still in aworkable condition in extreme cold weather. Still further, there is aneed to provide a more efficient heating and cooling heat pump system,as well as a more economical and safer system for household use.

SUMMARY OF THE INVENTION

A high energy efficient heat pump heating and cooling system, integratedwith solar and heat recovery system, is provided. According to thepresent invention, a heat recovery exchanger and a solar heat exchangerare integrated with the heat pump system. In heating mode, the workingmedium comes out of the compressor as hot high pressure gas. The heatrecovery exchanger cycles some of the heat from the high pressure gas toa domestic water heater providing hot water for normal household use.The medium coming out of the heat recovery exchanger is still warmenough to heat the inside of the building. Further, the solar exchangeruses the heat collected from a solar panel to provide supplementary heatto the system, thus reduce the workload of the heat pump system, makingit more energy efficient. In cooling mode, the compressor converts theworking medium into hot high pressure gas. This heat is recycled by theheat recovery exchanger to provide a heat source for the domestic waterheater, while helping reduce the load of the heat pump by reducing thetemperature of the working medium.

According to another aspect of the present invention, a buffer watertank is integrated with the heat pump system. The buffer water tank isan insulated water tank that contains water or anti-freeze fluid used tostore the energy generated from the heat pump. In heating or coolingmode, the water in the tank is heated or cooled by the working medium toa certain temperature and maintains at a steady temperature, deliveringheating or cooling to different areas of the building via low-pressurewater or anti-freeze economically and safely. Optionally, a water pumpsystem forces the working medium in the entire system or part of thesystem to constantly circulate thus maintains at a steady temperature.When user demands heating or cooling from the system, the working mediumwill be brought quickly to its ideal working temperature without thesystem having to heat or cool from zero-start.

According to another aspect of the present invention, a whole housesolar panel is integrated with the heat pump system to provideadditional heat for both the insulated buffer water tank and a domesticwater heater, thus making the heat pump system more energy efficient.According to another aspect of the present invention, a whole housesolar power and heating integrated system is integrated to the heat pumpsystem to provide additional heat as well electricity for the building.

According to another aspect of the present invention, the entire heatpump system is automatically controlled with an integrated intelligentcontroller for controlling various functions such as controlling thedirection of medium flow, pressure change valves, water pumps forcirculation, thermostat at various points in the system, solar panel andheat exchanger, and fan coil unit at each room of the building.According to another aspect of the present invention, the domestic waterheater can use a back up wall mount heat pump. Other applications mayalso become apparent as utilized by one skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 shows the functional diagram of an exemplary heat pump controllersystem according to one aspect of the present invention.

FIG. 2 shows an exemplary configuration of the heat pump heating andcooling system according to one aspect of the present invention.

FIG. 3 shows an exemplary configuration of the heat pump heating andcooling system according to one aspect of the present invention.

FIG. 4 shows an exemplary solar power and heating integrated device as areference.

FIG. 5 shows an exemplary water heater exchange system according to oneaspect of the present invention.

DETAILED DESCRIPTION

We disclose here a high energy efficient heat pump controller system bymeans of a design and construction example according to the presentinvention. This example, however, is not intended to limit the scope ofthe present invention.

For purposes of example, we will consider a heat pump system intended tooperate in both hot and extreme cold climate, for example at or above100° F. or below 0° F. outside. With reference to FIG. 1, a two-way heatpump system (100) comprises pipes (20) connecting between variouscomponents. By way of example, an environmental friendly heat transferworking medium R-410A is used. The medium flows in two directionsdepending on the working mode of the heat pump. In heating mode, themedium flows in direction 200; whereas in cooling mode the medium flowsin opposite direction (300).

In heating mode, the coil inside the condenser (15) works as a heatexchanger, in which the medium releases heat that in turn exchanges theheat with the water or anti-freeze water flowing from/to a buffer watertank (104 in FIG. 2). The heat exchange in turn heats the water in thebuffer water tank. The medium runs at about 40-60° C. as high pressuregas before entering the condenser/heat exchanger (15) and cools down toabout 30-45° C. as high pressure liquid. The water in the buffer watertank in return maintains at about 40-45° C. The medium further goesthrough a throttling expansion valve (16) to become low pressure liquid.Because of the expansion, the medium temperature also dropssignificantly to about −15˜10° C. The medium further arrives in lowpressure liquid at outdoor coil (18), which functions as evaporator inthe heating mode. By absorbing heat from the surrounding air, the mediumbecomes vaporized gas. At the same time, the medium also gets heated inthe solar heat exchanger (17) via heat collected from a solar heatingpanel (100 in FIG. 2), where its temperature may raise to −15˜15° C.depending on the efficiency of the solar panel. The use of the solarheat exchanger 17 thus helps improving the efficiency of the evaporator18 by providing supplementary heat. The vaporized gas travels through amulti-direction valve (13) and is compressed by a compressor (11) tobecome hot high pressure gas, at the temperature of about 70-85° C. Themedium then travels through a domestic water heat exchanger (12) to heatthe water in a domestic hot water tank (102 in FIG. 2) for householduse, coming out still as high pressure gas at about 40-60° C. beforeentering the condenser/heat exchanger (15). This cycles then repeats.

In cooling mode, the medium flow is just the opposite (300). The mediumarriving at the evaporator/heat exchanger coil (15) is in the form oflow pressure liquid at temperature around 5-15° C. It in turn cools downthe water in the buffer water tank (104 in FIG. 2) where the water ismaintained at about 7-12° C., while the temperature of the mediumincreases slightly to about 10-15° C. The medium travels throughmulti-direction valve (13) and arrives directly at the compressor (11)as cool low pressure liquid. There, the medium becomes hot high pressuregas at the temperature of about 70-80° C. The medium flows through thedomestic water heat exchanger (12) to heat the domestic living householdwater while reducing the temperature itself before it reaches theoutdoor condenser 18. This heat recovery process heats the domesticwater for household use while lowering the temperature in the workingmedium to about 40-60° C. The lowered temperature through this heatrecovery process will improve the efficiency of the condenser (18) thusthe efficiency of the entire heat pump system. The more the living wateris used, the more heat exchange occurs at the domestic water heatexchange 12, and the more efficient the heat pump system is. The mediumbypasses solar heat exchanger in the cooling mode, this can be realizedby an electronically controlled solenoid valve, which is commerciallyavailable. The medium then continue through throttling expansion valve(16) to become low pressure liquid at the temperature of about 5-15° C.before returning to the evaporator/heat exchange coil (15). The cyclerepeats.

An Exemplary Embodiment I

By way of example, FIG. 2 shows an exemplary heat pump system using theprinciple aforementioned. According to one aspect of the presentinvention, the exemplary system (120), as shown in FIG. 2, comprises aheat pump control subsystem (103), a solar heating subsystem (100),anti-freeze circulation pipes (106-113, 130, 131), a domestic hot watertank (102), a buffer water tank (104), an indoor fan coil subsystem(105) and optionally a wall-mounted heat pump (101). The heat pumpcontrol subsystem (103) is connected with a solar panel (100) thatprovides supplemental heat energy to the heat pump, making it moreefficient. The heat pump control subsystem (103) also connects with thebuffer water tank (104) that stores heated (in the heating mode) orcooled (in the cooling mode) water, to be ready to provide heating orcooling to the house on demand. Further, the heat pump control subsystem(103) connects to the indoor fan coil subsystem (105) that ventilateshot or cool air to inside the building on demand. The heat pump controlsubsystem (103) further connects to the domestic water heater (102) toprovide additional heat for providing tap hot water to inside thebuilding. Optionally, another supplementary heat pump or water heater(e.g. a wall mounted unit) is attached to the water heater (102) as abackup source to provide continued hot water supply to the house.

Heating Mode.

According to one aspect of the present invention, if the outside weatheris adequate, the solar subsystem (100) silicon photocell array assemblyproduces heat energy through heating the antifreeze liquid inside thepipes. The heated liquid flows to the heat exchanger (17 in FIG. 1) toprovide supplementary heat to the heat pump, thus reducing the burden onthe heat pump and making the system more efficient. For example, whenthe outside temperature is −13° F., there is very few heat energy in theair. The use of solar will improve the efficiency of the traditionalheat pump system as if it was working under a 50° F. air temperature,and the COP of the system can reach 3.0, which can not be achieved bytraditional heat pump.

The heat produced by the heat pump control subsystem (103) istransported to the buffer water tank (104) through the water oranti-freeze fluid inside the pipes (110 and 111), where the water insidethe buffer water tank maintains at a pre-set temperature, for example,in the range of 40-55° C. The temperature control is entirely automatic.Only when the temperature in the buffer water tank falls below a pre-setthreshold (e.g. 38° C.) will the cycle of the heat pump controlsubsystem (103) start. Similarly, when the temperature in the bufferwater tank reaches a preset threshold (e.g. 56° C.), the heat pump willbecome standby.

According to another aspect of the invention, the heat produced by theheat pump control subsystem (103) is transported to a domestic hot watertank (102) to provide hot water for use inside the house. The domestichot water tank (102) is different from traditional hot water heater thatuses electric coils or gas hot water that uses gas burner. The waterheated by the heat pump system may reach lukewarm that is sufficient forhand washing, laundry, dish washing or even shower. However, from apractical standpoint, the domestic hot water tank is also connected to abackup heating system or a secondary water heater to provide hightemperature hot water for household use. Alternatively, the heat pumpsystem can be integrated with a whole house solar system as a primarysource of heating for domestic hot water (FIG. 3). The domestic hotwater tank (102) for heat pump use is simple in construction in that itdoes not have any electric coils or gas burners. According to one aspectof the present invention, the heating exchanger (12 in FIG. 1) is builtinto the heat pump system thus all pipes containing the heat transferworking medium are reduced to minimum length, which can be made to becontained in a heat pump unit.

According to another aspect of the present invention, the heat exchangercan be made inside the domestic hot water tank, where the working mediumof the heat pump system flows through. With reference to FIG. 5, thewater heater comprises of an insulated tank (4), working medium inlet(1), coils (5) containing the working medium, fixtures (2, 6) for fixingthe coils to the tank (4), the working medium outlet (9), and the base(7). Filled in the tank is household tap water flowing in and out thewater tank in regular home pluming pipes. Coils (5) containing theworking medium are made from copper or other materials as commerciallyavailable. Optionally, a water pump for circulating the working mediumcan be installed at inlet or outlet of the coil (1 or 9) or othersection of the pipe systems. The cost associated with building suchwater heater is minimal, and is outweighed by the benefits in energysaving.

Cooling Mode.

According to another aspect of the invention, and with reference to FIG.2, the heat pump control subsystem (103) can work in a cooling modewhereas the working medium inside the pipes flows in the oppositedirection. When the medium comes out of the throttling expansion valve(16 in FIG. 1), the low temperature 5˜15° C. arrives at theevaporator/heat exchanger (15 in FIG. 1) to lower the water temperatureinside the buffer water tank (104), which is maintained at a predefinedtemperature range, for example, 7˜12° C. Similar to heating mode, thecycle of heat pump control subsystem (103) is entirely automaticallycontrolled depending on water temperature inside the buffer water tank(104). When the water temperatures drops to a predefined threshold, e.g.5° C., the heat pump system will become standby. When the watertemperature reaches a predefined threshold, e.g. 12° C., the heat pumpsystem will start the cooling cycle. In cooling mode, according to oneaspect of the present invention, the solar subsystem 17 will be shutoff. Instead, the condenser (18 in FIG. 1) is used to cool down themedium in the pipe before the medium reaches the throttling expansionvalve (16 in FIG. 1).

The structure of buffer water tank (104) is similar to that of thedomestic water heat (102) except that the buffer water tank is aconcealed unit such that the water (or other medium) cycles completelyin a concealed loop to various fan coil units inside the building. Theheat exchange coil for heating or cooling the buffer water tank (104)can be placed inside the heat pump system or inside the buffer watertank depending on the location of the buffer water tank.

Throttling expansion valves are readily commercially available, such asmodel AAE5 manufactured by AMS Electronics in Shenzhen, China. Waterpumps and valves aforementioned are also readily commercially available,which are commonly used in heating systems.

According to one aspect of the invention, and with reference to FIG. 2,a fan coil subsystem is installed inside the house, which isadvantageous to traditional forced air HVAC system that requires highinitial cost on installing duct pipes inside the house. Instead, the fancoil subsystem comprises ventilation fan and coils (105) installed ateach room or heating/cooling area inside the building, and PVC pipes(130, 131) connecting therefrom to the buffer water tank. While much ofthe heating/cooling and heat exchanging elements can be contained insidea heat pump control subsystem (103), the connection to in-house fan coilsubsystem is made by low cost PVC pipes containing water or anti-freezemedium at low pressure. This provides safe and environmental friendlyconfiguration as well as low installation cost inside the house incomparison to traditional forced air HVAC system. The PVC pipes forconnecting to fan coil subsystem are typically 0.5-1″ in diameter,making them much easier and economical to install inside a building thantraditional duct system. Fan coil units are commercially made in variousconfigurations such as vertical exposed, or concealed inside a wall orceiling. Such example is Trane's HFCA/XA, VFCA/XA fan coil unit thatprovides air flow of 300 m³/h˜2280 m³/h.

Inside the PVC pipes is the water or anti-freeze that circulates fromthe buffer water tank (104) through the fan coil subsystem and back tothe buffer water tank (104) in a concealed loop. According to one aspectof the invention, a water pump is installed in the pipe system andadapted to cause the water in certain zones of frequent demand tocirculate constantly at a relative stable temperature, even there is nodemand for heating or cooling. Each ventilation fan inside the buildingcan be turned on independently, heating or cooling only the specificroom/area on demand. When a ventilation fan is turned on, the water oranti-freeze will circulate through the coil inside the fan coil unit andthe fan blows out warm or cold air to the area. Each fan unit can becontrolled by a thermostat controller, allowing user to set a desiredtemperature in individual room or a zone inside the building. Once aroom or zone is set to a desired temperature, the water or anti-freezein that area circulates to/from the buffer water tank to bring heatingor cooling to the desired area, and the operation of the fan coil unitwill operate automatically until the desired temperature is reached.

According to one aspect of the present invention, the thermostat foreach room can have other functions such as timer, program setting and soon. While a fan unit is turned on, more energy is drawn to thatparticular room/area. First, the working medium inside the circulationpipe (130, 131) will bring needed energy to each living area throughrespective fan coil units (105) and bring the temperature of the area toa comfortable desired setting T1. At the same time, the automaticcontrol system (as part of the heat pump control subsystem) alsomonitors the temperature inside the buffer water tank (104). If thetemperature reaches above T2 in cooling mode or below T3 in heatingmode, the cycle of the heat pump subsystem (103) starts to bring thewater inside the buffer water tank (104) to the desired presettemperature. Normally, in heating mode, T1 is around 40° C. and T3 isaround 45° C., whereas in cooling mode T1 is around 7° C. and T2 isaround 12° C.

According to another aspect of the invention, when the water temperatureinside the buffer water tank exceeds a normal range, e.g. falls outsidethe 2° C.˜60° C., it is indicative of a malfunction of the system andthe heat pump is going into shut-off mode and user should be alerted ofthe situation.

According to one aspect of the present invention, the layout of thepipes (130, 131 in FIG. 2) can vary and can be designed for the systemto work at its best performance with minimum loss of energy. Forexample, pipes can be laid out by zones. Instead of a single pipe comingout of the buffer water tank, multiple pipes come out of and return tothe buffer water tank, each serving a different zone.

According to another aspect of the invention, a water pump is installedin the pipes for each zone to provide circulation of the working medium.Depending on the living style, the patterns of circulation of workingmedium inside each zone can differ. For zones that demand heating orcooling more frequently, the working medium can be circulated morefrequently or constantly, whereas for zones of lower demand the workingmedium can circulate infrequently or circulate only when it is needed.This would minimize the loss of energy when a zone is not in demandcompletely.

According to another aspect of the present invention, an intelligentenergy saving control subsystem can be installed to moderate theoperation of the system according to user's usage of energy. Forexample, the intelligent energy saving subsystem automatically monitoruser's setting in each area, frequency of use, duration of each demand,timing etc. According to one aspect of the present invention, if ademand for a particular zone can be predicted based on the past usage,and the system may prepare such demand by starting circulating theworking medium in that zone at a predetermined time (e.g. 5 minutes, 30minutes, 1 hour etc.) before such demand is expected. Once the demand isrequested, the temperature of the area in demand can be brought to thedesired level effectively in a short time.

The primary energy consumption is from the operation of the heat pumpcontrol subsystem to run the compressor, evaporator, condenser etc. Thispower consumption can be reduced by various components according to thepresent invention. For example, the integration of solar heating systemwill provide supplementary heat energy to raise the temperature of theworking medium, thus reduce the burden of the heat pump system. Further,the integration of the domestic water heating system also helps recoverwasted energy from the heat pump system while helping cooling down thetemperature of the working medium in the summer, thus again reducing theburden of the heat pump system. Still further, the integration of thebuffer water tank and careful design of the fan coil subsystem helpreduce the energy loss to minimum thus reduce the power consumption ofthe system. Various electronic controls and the operation of water pumpsare all low power consumption, needing only about 200 Watts for a systemserving a moderate size home.

An Exemplary Embodiment II

By way of example, FIG. 3 shows another exemplary heat pump systemaccording to one aspect of the present invention. With reference to FIG.3, a whole house solar power and heating system is integrated.

The use of solar energy can be divided into four categories, includinglight to heat (thermal use), light to electricity, light to chemicalutilization, and light to bio-utilization. In these four types of solarenergy uses, light to thermal conversion technology is the most mature,and many products are made at relatively low cost. For example, solarwater heaters, solar water boilers, solar dryers, solar cookers, solargreenhouse, solar house, solar desalination unit and solar heating andare seen in commercial use. Within this category, perhaps solar waterheaters have the most extensive use due to their mature technologies andeconomy. The solar light to heat system mainly converts collected solarradiation into heat. A typical solar collection device includes solarcollector, vacuum tube collectors and focusing collectors.

In converting solar into electricity power, there are mainly twomethods: one is light-heat-electricity conversion, namely generating theelectric power by solar radiation, in which process solar collectorsconvert thermal energy into steam of a working fluid and generate powerby steam-driven generators. This method is a combination of light tothermal conversion and heat to electricity conversion. The second methodis light to electricity conversion. The basic principle is to exchangesolar radiation directly into electricity with photovoltaic effect,using solar cells as the basic unit.

Integrated solar heating and power generation at the same time havehigher solar conversion efficiency than traditional photovoltaic powergeneration. For example, the U.S. patent application 2013/0269755 titled“Solar Glass Thermoelectric Integrated Device” to Songshun Xu teaches anintegrated solar heating and power generation device, which patent isincorporated by reference. A cross section of the device taught by Xu isalso shown in FIG. 4.

With reference to FIG. 3, a whole house solar power and heatingintegrated board (SPHIB) system (201) is integrated into the heat pumpsystem according to one aspect of the present invention. The SPHIBsystem generates electricity that is used by home appliances and otherdevices (200). The SPHIB system is connected to both the buffered watertank (104) through pipes (203, 204), where the pipes go through thesolar device (e.g. heat collecting tube 1 in FIG. 4). The heat generatedby SPHIB system is used to heat the water in the buffer water tank(104). Again, the medium circulating between the buffer water tank (104)and SPHIB system (201) and flowing through connecting pipes (203, 204)is water or anti-freeze fluid, operating in low pressure. Other mediummay be used as well. The SPHIB system (201) can be used as the primarysource of heating the water in the buffer water tank as it works moreeffectively and quickly in a sunny day even in the winter. In return,this significantly reduces the work load of the heat pump subsystem(103), thus making the heat pump subsystem secondary because it does nothave to work as hard to heat the water in the buffer water tank.Depending on the number of solar panels used in the SPHIB system (201),the efficiency of the heat pump system varies. The more solar panels theSPHIB uses, the more efficient the heat pump system is.

According to one aspect of the present invention, the integrated solarheating subsystem (100) can still be used standalone for the heat pumpcontrol subsystem (103) as a supplementary source of energy. The solarheating subsystem (100) does not need to be of large size and it can beversatile and portable without requiring to install a whole house solarsystem. In a typical configuration, the solar heating subsystem (100)can be 2 square meters in area (with about 1.85 square meters of heatcollecting area). According to another aspect of the present invention,the solar heating subsystem (100) can be substituted by the whole housesolar system SPHIB (201). This is particular desirable if the wholehouse solar system is already installed. In this case, pipes can beinstalled to connect the heat pump control subsystem (103) and the wholehouse solar system SPHIB heating pipes in the similar fashion as thebuffer water heater (104).

According to another aspect of the present invention, the whole housesolar system (201) is connected to the domestic water heater (102),where the heat collected from the solar system is carried by the workingmedium flowing in the pipes (202, 205) to the water heater (102), whereit heats the tap water for household use. This works for both heatingand cooling mode, similar to the embodiment as shown in FIG. 2, with thedifference that the SPHIB can work as a primary heating source for thedomestic water heater.

The solar heating and cooling system and various embodiments aredisclosed here only to show various aspects of the present invention.Extensions, variations as may be clear to one skilled in the art shallnot depart from the scope of the present invention. For example, theworking medium used in the pipes can be different from R401A as requiredby the demand. Other medium such as R-744 or more environment friendlymedium, such as R600A or other medium to be later developed, may also beused.

Further, as different medium may require different working pressure,different pipes may be used to accommodate this requirement. Accordingto one aspect of the present invention, PVC pipes with copper orstainless steel core, which are commercially available, are used.Although all PVC pipes that are exposed to outdoor climate are insulatedto prevent freezing inside, PVC pipes with copper or stainless coregives special advantages to withstanding cold or hot, e.g. −40° F.˜204°F., and prevents pipe burst from freezing. Other pipes may also be usedas justified by their cost and requirement.

Further, to withstand extreme cold weather, other than the condenser (18in FIG. 1), all components can be place indoors. In this way, the systemcan still work under −25° C. Still further, the medium inside the bufferwater can be water or other anti-freeze fluid, and the heat exchangecoil can be inside the tank (104 in FIG. 2) or inside the heat pumpsubsystem (103 in FIG. 2). If the heat exchange coil (15 in FIG. 1) isinstalled inside the heat pump subsystem, then the buffer water tankwill be structured as an empty tank and functions as a water storageonly, reducing the cost of the tank even further.

Still further variations, including combinations and/or alternativeimplementations, of the embodiments described herein can be readilyobtained by one skilled in the art without burdensome and/or undueexperimentation. Such variations are not to be regarded as a departurefrom the spirit and scope of the invention.

1. A heat pump heating and cooling system for working in a heating orcooling mode comprising: a first heat transfer medium; a heat pumpcontrol subsystem comprising a compressor, an evaporator, a condenserand an expansion valve, containing the first heat transfer mediumtherein and adapted to operate in a heating or cooling mode; a firstheat exchanger connected to a buffer water tank for transferring heatbetween the first heat transfer medium contained in the heat pumpcontrol subsystem and a second heat transfer medium contained in thebuffer water tank; a second heat exchanger connected to a solar heatsubsystem and adapted for providing supplementary heat to said heat pumpcontrol subsystem in the heating mode; and a third heat exchangerconnected to a domestic water heater and adapted for transferring heatproduced from the said heat pump control subsystem to the domestic waterheater; whereby said buffer water tank containing an inlet and an outletadapted to connect to one or more fan coil units carrying a flow of thesecond heat transfer medium for heat delivery.
 2. The system of claim 1,wherein the first heat transfer medium is one of the R-410A, R-744 andR600.
 3. The system of claim 1, wherein the second heat transfer mediumis water or anti-freeze fluid.
 4. The system of claim 1, wherein thefirst heat exchanger is adapted to be installed inside the buffer watertank.
 5. The system of claim 1, wherein the first heat exchanger isadapted to be installed inside the heat pump control subsystem.
 6. Thesystem of claim 1, wherein the solar heat subsystem is a solar heatcollecting panel or a whole house solar heating system.
 7. The system ofclaim 1, wherein the solar heat subsystem is a whole house solarthermoelectric integrated system.
 8. The system of claim 1, wherein thesolar heat subsystem is connected to the buffer water tank and adaptedto provide supplementary heat to said heat pump control subsystem. 9.The system of claim 1 further comprising a control circuit is adapted tomaintain the temperature of the second heat transfer medium contained inthe buffer water tank within a first preset range.
 10. The system ofclaim 9, wherein the control circuit is adapted to control operation ofone or more fan coil units to maintain interior temperature within asecond preset range.
 11. The system of claim 9, wherein the controlcircuit is adapted to estimate a start time based on past usage of thesystem and kick-start the heat pump control subsystem at a predefinedinterval time before said estimated start time.
 12. A heat pump heatingand cooling system for working in a heating or cooling mode comprising:a first heat transfer medium; a heat pump control subsystem comprising acompressor, an evaporator, a condenser and an expansion valve,containing the first heat transfer medium therein and adapted to operatein a heating or cooling mode; a first heat exchanger connected to abuffer water tank for transferring heat between the first heat transfermedium contained in the heat pump control subsystem and a second heattransfer medium contained in the buffer water tank; a second heatexchanger connected to a domestic water heater and adapted fortransferring heat produced from said heat pump control subsystem to thedomestic water heater; whereby said buffer water tank containing aninlet and an outlet adapted to connect to one or more fan coil unitscarrying a flow of the second heat transfer medium for heat delivery.13. The system of claim 12, wherein the first heat transfer medium isone of the R-410A, R-744 and R600.
 14. The system of claim 12, whereinthe second heat transfer medium is water or anti-freeze fluid.
 15. Thesystem of claim 12, wherein the first heat exchanger is adapted to beinstalled inside the heat pump control subsystem.
 16. The system ofclaim 12 further comprising a solar heat subsystem adapted to providesupplementary heat to the heat pump control subsystem in the heatingmode.
 17. The system of claim 12 further comprising a solar heatsubsystem connected to the buffer water tank and adapted to providesupplementary heat to the second heat transfer medium contained therein.18. The system of claim 12 further comprising a control circuit isadapted to maintain the temperature of the second heat transfer mediumcontained in the buffer water tank within a first preset range.
 19. Thesystem of claim 18, wherein the control circuit is adapted to controloperation of one or more fan coil units to maintain interior temperaturewithin a second preset range.
 20. The system of claim 18, wherein thecontrol circuit is adapted to estimate a start time based on past usageof the system and kick-start the system at a predefined interval timebefore said estimated start time.
 21. The system of claim 12 furthercomprising a plurality of pipes carrying flow of the second heattransfer medium, wherein at least one of the plurality of pipes is madeof PVC/copper or PVC/stainless steel composite material.